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        1. MEGS_Log version 3.3 Help

          1. Copyright notice and licence agreement

          2. How to contact MEGS_Log support

          3. What's new in MEGS_Log 3.3

          4. Concepts in MEGS_Log

            1. About boreholes, units and elements

            2. About geophysical traces

            3. About editing with the mouse and Editing Tools

            4. About Insert Modes

            5. About schemas

            6. About seams and plies

            7. About sample numbers

            8. About hatches

            9. MEGS_Log settings

            10. About the MEGS_Log configuration file

            11. About MEGS_Log licencing

          5. How to carry out common tasks within MEGS_Log

          6. Menus and commands

          7. Window elements and dialogs

          8. List of appendices

          9. MEGS_Log version 3.3 Help Index

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About boreholes, units and elements

In MEGS_Log terminology a borehole is a collection of units arranged one on top of the other. Each unit occupies a unique vertical section in the borehole. Units cannot overlap.

Editing the vertical section that a unit occupies is one of the basic functions of MEGS_Log. MEGS_Log can also insert and delete units within the borehole.

Within each unit there can be one or more elements . Each element represents a type of material (or rock type) that is found within the unit.

Often a unit contains only one element - this indicates that the vertical section is practically occupied by only one rock type.

Where a unit contains more than one element it indicates that there is a mix of rock types present in the vertical section, possibly logged that way because bedding or similar prevented the materials from being practically separated out into their own intervals.

MEGS_Log draws the elements within a unit side by side on the graphical borehole display, occupying the same proportion of the interval as the percentage assigned to the element. The rock type assigned to an element is used by MEGS_Log to determine the hatch that should be used to fill in the area of the element.

Each element within a unit must be assigned a percentage to represent the proportion of the interval that the element occupies. The sum of the percentages across the elements within a unit must add to 100%.

MEGS_Log can be used to change the rock type associated with an element, the number of elements within a unit and the percentage of the interval that each element occupies.

Units can be assigned a sample number. Different intervals within the one borehole can have the same sample number. Sample numbers can have any format, however MEGS_Log generally can recognise if some sort of numeric sequence is in use and will prompt appropriately when new sample numbers are being assigned within a hole. See About sample numbers for more information

Units can also be assigned a seam or seam and ply name. This process is known within MEGS_Log as correlation. Different intervals within the one borehole can have the same seam/ply name. The set of seams and seam/ply combinations available is restricted to what has been defined in the MEGS_Log configuration for the currently selected site.